Herniation of the urinary bladder into an inguinal or femoral hernia has been known since the Middle Ages, with the first record of this entity by Plater in 1550 (10). The radiographic demonstration of such a hernia is uncommon, despite its description by Robins as early as 1929 (7). The incidence of bladder herniation in patients with inguinal hernia has been estimated at 1 to 3 per cent by some authors (4, 8) and as high as 10 per cent by Iason (2). Because of the proximity of the bladder to the inguinal and femoral canals, the degree of herniation will vary from a small protrusion to a massive one which represents less than 1 per cent of the bladder hernias. The majority of patients are males over the age of fifty with either direct or indirect inguinal hernias. Watson reports a l-to-3 ratio of femoral-to-inguinal bladder herniations, with the femoral more common in women, in conformity with the usual predominance of femoral hernias in females. Interesting, but not explained, is the fact that the major...